1. Field Of The Invention:
The present invention relates to a process for sealing roof seams in a sloped metal roof by the application of a thin strip of hot melt bituminous composite material to the roof seam alone.
2. Description Of Prior Art:
Metal buildings are in widespread use for a number of industrial and other applications. Typically, such buildings have sloped metal roofs, wherein corrugated metal sheets are mounted in overlapping fashion on an underlying roof framework by metal fasteners. A so-called "standing seam" metal roof is considered herein to be a corrugated metal roof. When new, roofing sheets are typically pre-painted and are fastened down by screws, with overlapping seams having a caulk-type of sealer between the overlapping portions of the seam. The screws have neoprene gaskets sealing the openings in the roof sheeting beneath the heads of the threaded fasteners. Sloped metal roofs are largely self-supporting and rely on the slope of the roof to minimize damage due to snow, ice, and water build-up on the roof. The corrugations in the metal sheeting are responsible for the deflection resistance of the roof.
Over a period of time, a sloped metal roof is subject to the adverse affects of weather. Ultraviolet radiation eventually disintegrates the neoprene gaskets around the fasteners, until the fasteners become loose. The weight of snow and other weather effects on the roof cause the overlapping sheets of roofing to move relative to each other, and the loosened screws facilitate this movement. The movement wears and causes cracks in the dried out caulk between the overlapping roof seams and eventually produces leaks in the roof seams.
A sloped metal roof cannot be repaired in the same way that a flat roof is repaired, which is typically by recovering the entire roof surface with a heavy roofing product or membrane formed of bituminous (asphalt) or composite materials. A sloped metal roof is not designed to support a lot of weight and cannot withstand the weight of such heavy roofing products over the entire roof. For many years, one typical way of resealing a sloped metal roof has been to apply caulk over the seams, apply a layer of screen over the caulk and then apply another layer of caulk over the screen. A "peel-and-stick" butyl tape or other such membrane applied over the roof seams also are known processes.
The problem with the known processes is, simply, that they do not work very well, and the roof returns to its leaky condition over a short period of time.
An object of the present invention is to overcome the long existing problem of sealing roof seams in a sloped metal roof.